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<a href="perf__fwd_8hpp.html">Go to the documentation of this file.</a><div class="fragment"><div class="line"><a id="l00001" name="l00001"></a><span class="lineno">    1</span><span class="comment">/* Flow</span></div>
<div class="line"><a id="l00002" name="l00002"></a><span class="lineno">    2</span><span class="comment"> * Copyright 2023 Akamai Technologies, Inc.</span></div>
<div class="line"><a id="l00003" name="l00003"></a><span class="lineno">    3</span><span class="comment"> *</span></div>
<div class="line"><a id="l00004" name="l00004"></a><span class="lineno">    4</span><span class="comment"> * Licensed under the Apache License, Version 2.0 (the</span></div>
<div class="line"><a id="l00005" name="l00005"></a><span class="lineno">    5</span><span class="comment"> * &quot;License&quot;); you may not use this file except in</span></div>
<div class="line"><a id="l00006" name="l00006"></a><span class="lineno">    6</span><span class="comment"> * compliance with the License.  You may obtain a copy</span></div>
<div class="line"><a id="l00007" name="l00007"></a><span class="lineno">    7</span><span class="comment"> * of the License at</span></div>
<div class="line"><a id="l00008" name="l00008"></a><span class="lineno">    8</span><span class="comment"> *</span></div>
<div class="line"><a id="l00009" name="l00009"></a><span class="lineno">    9</span><span class="comment"> *   https://www.apache.org/licenses/LICENSE-2.0</span></div>
<div class="line"><a id="l00010" name="l00010"></a><span class="lineno">   10</span><span class="comment"> *</span></div>
<div class="line"><a id="l00011" name="l00011"></a><span class="lineno">   11</span><span class="comment"> * Unless required by applicable law or agreed to in</span></div>
<div class="line"><a id="l00012" name="l00012"></a><span class="lineno">   12</span><span class="comment"> * writing, software distributed under the License is</span></div>
<div class="line"><a id="l00013" name="l00013"></a><span class="lineno">   13</span><span class="comment"> * distributed on an &quot;AS IS&quot; BASIS, WITHOUT WARRANTIES OR</span></div>
<div class="line"><a id="l00014" name="l00014"></a><span class="lineno">   14</span><span class="comment"> * CONDITIONS OF ANY KIND, either express or implied.</span></div>
<div class="line"><a id="l00015" name="l00015"></a><span class="lineno">   15</span><span class="comment"> * See the License for the specific language governing</span></div>
<div class="line"><a id="l00016" name="l00016"></a><span class="lineno">   16</span><span class="comment"> * permissions and limitations under the License. */</span></div>
<div class="line"><a id="l00017" name="l00017"></a><span class="lineno">   17</span><span class="comment"></span> </div>
<div class="line"><a id="l00018" name="l00018"></a><span class="lineno">   18</span><span class="comment">/// @file</span></div>
<div class="line"><a id="l00019" name="l00019"></a><span class="lineno">   19</span><span class="comment"></span><span class="preprocessor">#pragma once</span></div>
<div class="line"><a id="l00020" name="l00020"></a><span class="lineno">   20</span> </div>
<div class="line"><a id="l00021" name="l00021"></a><span class="lineno">   21</span><span class="preprocessor">#include &quot;<a class="code" href="clock__type__fwd_8hpp.html">flow/perf/clock_type_fwd.hpp</a>&quot;</span></div>
<div class="line"><a id="l00022" name="l00022"></a><span class="lineno">   22</span><span class="comment"></span> </div>
<div class="line"><a id="l00023" name="l00023"></a><span class="lineno">   23</span><span class="comment">/**</span></div>
<div class="line"><a id="l00024" name="l00024"></a><span class="lineno">   24</span><span class="comment"> * Flow module containing tools for profiling and optimization.</span></div>
<div class="line"><a id="l00025" name="l00025"></a><span class="lineno">   25</span><span class="comment"> *</span></div>
<div class="line"><a id="l00026" name="l00026"></a><span class="lineno">   26</span><span class="comment"> * As of this writing (around the time the flow::perf Flow module was created) this centers on Checkpointing_timer,</span></div>
<div class="line"><a id="l00027" name="l00027"></a><span class="lineno">   27</span><span class="comment"> * a facility for measuring real and processor time elapsed during the arbitrary measured operation.  That said,</span></div>
<div class="line"><a id="l00028" name="l00028"></a><span class="lineno">   28</span><span class="comment"> * generally speaking, this module is meant to be a &quot;kitchen-sink&quot; set of facilities fitting the sentence at the</span></div>
<div class="line"><a id="l00029" name="l00029"></a><span class="lineno">   29</span><span class="comment"> * very top of this doc header.</span></div>
<div class="line"><a id="l00030" name="l00030"></a><span class="lineno">   30</span><span class="comment"> */</span></div>
<div class="line"><a id="l00031" name="l00031"></a><span class="lineno">   31</span><span class="keyword">namespace </span><a class="code hl_namespace" href="namespaceflow_1_1perf.html">flow::perf</a></div>
<div class="line"><a id="l00032" name="l00032"></a><span class="lineno">   32</span>{</div>
<div class="line"><a id="l00033" name="l00033"></a><span class="lineno">   33</span><span class="comment">// Types.</span></div>
<div class="line"><a id="l00034" name="l00034"></a><span class="lineno">   34</span> </div>
<div class="line"><a id="l00035" name="l00035"></a><span class="lineno">   35</span><span class="comment">// Find doc headers near the bodies of these compound types.</span></div>
<div class="line"><a id="l00036" name="l00036"></a><span class="lineno">   36</span> </div>
<div class="line"><a id="l00037" name="l00037"></a><span class="lineno">   37</span><span class="keyword">class </span>Checkpointing_timer;</div>
<div class="line"><a id="l00038" name="l00038"></a><span class="lineno">   38</span><span class="comment"></span> </div>
<div class="line"><a id="l00039" name="l00039"></a><span class="lineno">   39</span><span class="comment">/**</span></div>
<div class="line"><a id="l00040" name="l00040"></a><span class="lineno">   40</span><span class="comment"> * Short-hand for ref-counting pointer to Checkpointing_timer.  Original use case is to allow</span></div>
<div class="line"><a id="l00041" name="l00041"></a><span class="lineno">   41</span><span class="comment"> * Checkpointing_timer::Aggregator to generate and return Checkpointing_timer objects with minimal headaches for user.</span></div>
<div class="line"><a id="l00042" name="l00042"></a><span class="lineno">   42</span><span class="comment"> */</span></div>
<div class="line"><a id="l00043" name="l00043"></a><span class="lineno"><a class="line" href="namespaceflow_1_1perf.html#a09ba385403a0f347f283659a6e9d971b">   43</a></span><span class="keyword">using </span><a class="code hl_typedef" href="namespaceflow_1_1perf.html#a09ba385403a0f347f283659a6e9d971b">Checkpointing_timer_ptr</a> = boost::shared_ptr&lt;Checkpointing_timer&gt;;</div>
<div class="line"><a id="l00044" name="l00044"></a><span class="lineno">   44</span> </div>
<div class="line"><a id="l00045" name="l00045"></a><span class="lineno">   45</span><span class="comment">// Free functions.</span></div>
<div class="line"><a id="l00046" name="l00046"></a><span class="lineno">   46</span><span class="comment"></span> </div>
<div class="line"><a id="l00047" name="l00047"></a><span class="lineno">   47</span><span class="comment">/**</span></div>
<div class="line"><a id="l00048" name="l00048"></a><span class="lineno">   48</span><span class="comment"> * Constructs a closure that times and executes `void`-returning `function()`, adding the elapsed time with</span></div>
<div class="line"><a id="l00049" name="l00049"></a><span class="lineno">   49</span><span class="comment"> * clock type `clock_type` -- as raw ticks of perf::Duration -- to `accumulator`.</span></div>
<div class="line"><a id="l00050" name="l00050"></a><span class="lineno">   50</span><span class="comment"> *</span></div>
<div class="line"><a id="l00051" name="l00051"></a><span class="lineno">   51</span><span class="comment"> * Consider other overload(s) and similarly named functions as well.  With this one you get:</span></div>
<div class="line"><a id="l00052" name="l00052"></a><span class="lineno">   52</span><span class="comment"> *   - `function()` is treated as returning `void` (any return value is ignored).</span></div>
<div class="line"><a id="l00053" name="l00053"></a><span class="lineno">   53</span><span class="comment"> *   - `function()` is a generally-used timed function: not necessarily a `boost.asio` or flow::async *handler*.</span></div>
<div class="line"><a id="l00054" name="l00054"></a><span class="lineno">   54</span><span class="comment"> *     Any associated executor (such as a `strand`) *will* be lost.  See timed_handler(), if you have a handler.</span></div>
<div class="line"><a id="l00055" name="l00055"></a><span class="lineno">   55</span><span class="comment"> *   - One specific perf::Clock_type, not some subset given as perf::Clock_types_subset.  For performance this may</span></div>
<div class="line"><a id="l00056" name="l00056"></a><span class="lineno">   56</span><span class="comment"> *     be significant, even though operations on the latter are still light-weight.</span></div>
<div class="line"><a id="l00057" name="l00057"></a><span class="lineno">   57</span><span class="comment"> *   - Accumulation (the plus-equals operation) done by performing `+=(duration_rep_t)`, where perf::duration_rep_t</span></div>
<div class="line"><a id="l00058" name="l00058"></a><span class="lineno">   58</span><span class="comment"> *     is -- as a reminder -- a raw integer type like `int64_t`.  If accumulation may occur in a multi-threaded</span></div>
<div class="line"><a id="l00059" name="l00059"></a><span class="lineno">   59</span><span class="comment"> *     situation concurrently, this can improve performance vs. using an explicit lock, if one</span></div>
<div class="line"><a id="l00060" name="l00060"></a><span class="lineno">   60</span><span class="comment"> *     uses `Accumulator` = `atomic&lt;duration_rep_t&gt;`.</span></div>
<div class="line"><a id="l00061" name="l00061"></a><span class="lineno">   61</span><span class="comment"> *   - Lack of `chrono`-style type safety: It is up to you to interpret the `*accumulator`-stored ticks as their</span></div>
<div class="line"><a id="l00062" name="l00062"></a><span class="lineno">   62</span><span class="comment"> *     appropriate units.</span></div>
<div class="line"><a id="l00063" name="l00063"></a><span class="lineno">   63</span><span class="comment"> *</span></div>
<div class="line"><a id="l00064" name="l00064"></a><span class="lineno">   64</span><span class="comment"> * ### Synopsis/examples ###</span></div>
<div class="line"><a id="l00065" name="l00065"></a><span class="lineno">   65</span><span class="comment"> * Time a function that happens to take a couple of args.  Don&#39;t worry about the timing also happening concurrenty:</span></div>
<div class="line"><a id="l00066" name="l00066"></a><span class="lineno">   66</span><span class="comment"> * not using `atomic`.</span></div>
<div class="line"><a id="l00067" name="l00067"></a><span class="lineno">   67</span><span class="comment"> *</span></div>
<div class="line"><a id="l00068" name="l00068"></a><span class="lineno">   68</span><span class="comment"> *   ~~~</span></div>
<div class="line"><a id="l00069" name="l00069"></a><span class="lineno">   69</span><span class="comment"> *   flow::perf::duration_rep_t accumulated_ticks(0);</span></div>
<div class="line"><a id="l00070" name="l00070"></a><span class="lineno">   70</span><span class="comment"> *   const auto timed_func</span></div>
<div class="line"><a id="l00071" name="l00071"></a><span class="lineno">   71</span><span class="comment"> *     = flow::perf::timed_function</span></div>
<div class="line"><a id="l00072" name="l00072"></a><span class="lineno">   72</span><span class="comment"> *         (flow::perf::Clock_type::S_CPU_THREAD_TOTAL_HI_RES, &amp;accumulated_ticks,</span></div>
<div class="line"><a id="l00073" name="l00073"></a><span class="lineno">   73</span><span class="comment"> *          [](int x, int y) { for (auto i = 0; i &lt; (x * y); ++i) {} });</span></div>
<div class="line"><a id="l00074" name="l00074"></a><span class="lineno">   74</span><span class="comment"> *   // ...</span></div>
<div class="line"><a id="l00075" name="l00075"></a><span class="lineno">   75</span><span class="comment"> *   // Later, run it -- this will add to accumulated_ticks.  Can do this many times but not concurrently.</span></div>
<div class="line"><a id="l00076" name="l00076"></a><span class="lineno">   76</span><span class="comment"> *   timed_func(7, 7); // Note it can only be called void-style.</span></div>
<div class="line"><a id="l00077" name="l00077"></a><span class="lineno">   77</span><span class="comment"> *   // ...</span></div>
<div class="line"><a id="l00078" name="l00078"></a><span class="lineno">   78</span><span class="comment"> *   // Later, here&#39;s the result.  Note the construction from type-unsafe ticks to type-safe Duration.</span></div>
<div class="line"><a id="l00079" name="l00079"></a><span class="lineno">   79</span><span class="comment"> *   const flow::perf::Duration total_dur(accumulated_ticks);</span></div>
<div class="line"><a id="l00080" name="l00080"></a><span class="lineno">   80</span><span class="comment"> *   // Can convert to whatever units type-safely now (duration_cast&lt;&gt; in this case allows for precision loss).</span></div>
<div class="line"><a id="l00081" name="l00081"></a><span class="lineno">   81</span><span class="comment"> *   const auto total_dur_us = chrono::duration_cast&lt;chrono::microseconds&gt;(total_dur);</span></div>
<div class="line"><a id="l00082" name="l00082"></a><span class="lineno">   82</span><span class="comment"> *   ~~~</span></div>
<div class="line"><a id="l00083" name="l00083"></a><span class="lineno">   83</span><span class="comment"> *</span></div>
<div class="line"><a id="l00084" name="l00084"></a><span class="lineno">   84</span><span class="comment"> * Same thing but with an `atomic` to support timing/execution occuring concurrently:</span></div>
<div class="line"><a id="l00085" name="l00085"></a><span class="lineno">   85</span><span class="comment"> *</span></div>
<div class="line"><a id="l00086" name="l00086"></a><span class="lineno">   86</span><span class="comment"> *   ~~~</span></div>
<div class="line"><a id="l00087" name="l00087"></a><span class="lineno">   87</span><span class="comment"> *   std::atomic&lt;flow::perf::duration_rep_t&gt; accumulated_ticks(0);</span></div>
<div class="line"><a id="l00088" name="l00088"></a><span class="lineno">   88</span><span class="comment"> *   const auto timed_func</span></div>
<div class="line"><a id="l00089" name="l00089"></a><span class="lineno">   89</span><span class="comment"> *     = flow::perf::timed_function</span></div>
<div class="line"><a id="l00090" name="l00090"></a><span class="lineno">   90</span><span class="comment"> *         (flow::perf::Clock_type::S_CPU_THREAD_TOTAL_HI_RES, &amp;accumulated_ticks,</span></div>
<div class="line"><a id="l00091" name="l00091"></a><span class="lineno">   91</span><span class="comment"> *          [](int x, int y) { for (auto i = 0; i &lt; (x * y); ++i) {} });</span></div>
<div class="line"><a id="l00092" name="l00092"></a><span class="lineno">   92</span><span class="comment"> *   // ...</span></div>
<div class="line"><a id="l00093" name="l00093"></a><span class="lineno">   93</span><span class="comment"> *   // Later, run it -- this will add to accumulated_ticks.  Can do this many times *and* concurrently in N threads.</span></div>
<div class="line"><a id="l00094" name="l00094"></a><span class="lineno">   94</span><span class="comment"> *   timed_func(7, 7); // Note it can only be called void-style.</span></div>
<div class="line"><a id="l00095" name="l00095"></a><span class="lineno">   95</span><span class="comment"> *   // ...</span></div>
<div class="line"><a id="l00096" name="l00096"></a><span class="lineno">   96</span><span class="comment"> *   // Later, here&#39;s the result.  Note the construction from type-unsafe ticks to type-safe Duration.</span></div>
<div class="line"><a id="l00097" name="l00097"></a><span class="lineno">   97</span><span class="comment"> *   const flow::perf::Duration total_dur(accumulated_ticks);</span></div>
<div class="line"><a id="l00098" name="l00098"></a><span class="lineno">   98</span><span class="comment"> *   // Can convert to whatever units type-safely now (duration_cast&lt;&gt; in this case allows for precision loss).</span></div>
<div class="line"><a id="l00099" name="l00099"></a><span class="lineno">   99</span><span class="comment"> *   const auto total_dur_us = chrono::duration_cast&lt;chrono::microseconds&gt;(total_dur);</span></div>
<div class="line"><a id="l00100" name="l00100"></a><span class="lineno">  100</span><span class="comment"> *   ~~~</span></div>
<div class="line"><a id="l00101" name="l00101"></a><span class="lineno">  101</span><span class="comment"> *</span></div>
<div class="line"><a id="l00102" name="l00102"></a><span class="lineno">  102</span><span class="comment"> * ### `Accumulator A` type requirements/recommendations ###</span></div>
<div class="line"><a id="l00103" name="l00103"></a><span class="lineno">  103</span><span class="comment"> * It must have `A += duration_rep_t(...)`.  This operation must be safe for concurrent execution with itself, if</span></div>
<div class="line"><a id="l00104" name="l00104"></a><span class="lineno">  104</span><span class="comment"> * timed_function() is potentially used concurrently.  In that case consider `atomic&lt;duration_rep_t&gt;`.  If concurrency</span></div>
<div class="line"><a id="l00105" name="l00105"></a><span class="lineno">  105</span><span class="comment"> * is not a concern, you can just use `duration_rep_t` to avoid the strict-ordering overhead involved in `atomic`</span></div>
<div class="line"><a id="l00106" name="l00106"></a><span class="lineno">  106</span><span class="comment"> * plus-equals operation.</span></div>
<div class="line"><a id="l00107" name="l00107"></a><span class="lineno">  107</span><span class="comment"> *</span></div>
<div class="line"><a id="l00108" name="l00108"></a><span class="lineno">  108</span><span class="comment"> * `Accumulator` is understood to store raw ticks of #Duration -- not actual #Duration -- for performance reasons</span></div>
<div class="line"><a id="l00109" name="l00109"></a><span class="lineno">  109</span><span class="comment"> * (to wit: so that `atomic` plus-equals can be made use of, if it exists).  If you need a #Duration</span></div>
<div class="line"><a id="l00110" name="l00110"></a><span class="lineno">  110</span><span class="comment"> * ultimately -- and for type safety you really *should* -- it is up to you to construct a #Duration from the</span></div>
<div class="line"><a id="l00111" name="l00111"></a><span class="lineno">  111</span><span class="comment"> * accumulated `duration_rep_t`.  This is trivially done via the `Duration(duration_rep_t)` constructor.</span></div>
<div class="line"><a id="l00112" name="l00112"></a><span class="lineno">  112</span><span class="comment"> *</span></div>
<div class="line"><a id="l00113" name="l00113"></a><span class="lineno">  113</span><span class="comment"> * @todo timed_function(), when operating on an `atomic&lt;duration_rep_t&gt;`, uses `+=` for accumulation which may be</span></div>
<div class="line"><a id="l00114" name="l00114"></a><span class="lineno">  114</span><span class="comment"> * lock-free but uses strict ordering; a version that uses `fetch_add()` with relaxed ordering may be desirable</span></div>
<div class="line"><a id="l00115" name="l00115"></a><span class="lineno">  115</span><span class="comment"> * for extra performance at the cost of not-always-up-to-date accumulation results in all threads.</span></div>
<div class="line"><a id="l00116" name="l00116"></a><span class="lineno">  116</span><span class="comment"> * As of this writing this can be done by the user by providing a custom type that defines `+=` as explicitly</span></div>
<div class="line"><a id="l00117" name="l00117"></a><span class="lineno">  117</span><span class="comment"> * using `fetch_add()` with relaxed ordering; but we could provide an API for this.</span></div>
<div class="line"><a id="l00118" name="l00118"></a><span class="lineno">  118</span><span class="comment"> *</span></div>
<div class="line"><a id="l00119" name="l00119"></a><span class="lineno">  119</span><span class="comment"> * @todo timed_function() overload exists for a single `Clock_type`, but simultaneous multi-clock timing using the</span></div>
<div class="line"><a id="l00120" name="l00120"></a><span class="lineno">  120</span><span class="comment"> * perf::Clock_types_subset paradigm (as used, e.g., in Checkpointing_timer) would be a useful and consistent API.</span></div>
<div class="line"><a id="l00121" name="l00121"></a><span class="lineno">  121</span><span class="comment"> * E.g., one could measure user and system elapsed time simultaneously.  As of this writing this only does not exist</span></div>
<div class="line"><a id="l00122" name="l00122"></a><span class="lineno">  122</span><span class="comment"> * due to time constraints: a perf-niggardly version targeting one clock type was necessary.</span></div>
<div class="line"><a id="l00123" name="l00123"></a><span class="lineno">  123</span><span class="comment"> *</span></div>
<div class="line"><a id="l00124" name="l00124"></a><span class="lineno">  124</span><span class="comment"> * @tparam Accumulator</span></div>
<div class="line"><a id="l00125" name="l00125"></a><span class="lineno">  125</span><span class="comment"> *         Integral accumulator of clock ticks.  See above for details.</span></div>
<div class="line"><a id="l00126" name="l00126"></a><span class="lineno">  126</span><span class="comment"> * @tparam Func</span></div>
<div class="line"><a id="l00127" name="l00127"></a><span class="lineno">  127</span><span class="comment"> *         A function that is called `void`-style taking any arbitrary number of args, possibly none.</span></div>
<div class="line"><a id="l00128" name="l00128"></a><span class="lineno">  128</span><span class="comment"> * @param clock_type</span></div>
<div class="line"><a id="l00129" name="l00129"></a><span class="lineno">  129</span><span class="comment"> *        The type of clock to use for timing `function()`.</span></div>
<div class="line"><a id="l00130" name="l00130"></a><span class="lineno">  130</span><span class="comment"> * @param accumulator</span></div>
<div class="line"><a id="l00131" name="l00131"></a><span class="lineno">  131</span><span class="comment"> *        The accumulator to add time elapsed when calling `function()` to.  See instructions above regarding</span></div>
<div class="line"><a id="l00132" name="l00132"></a><span class="lineno">  132</span><span class="comment"> *        concurrency, `atomic`, etc.</span></div>
<div class="line"><a id="l00133" name="l00133"></a><span class="lineno">  133</span><span class="comment"> * @param function</span></div>
<div class="line"><a id="l00134" name="l00134"></a><span class="lineno">  134</span><span class="comment"> *        The function to execute and time.</span></div>
<div class="line"><a id="l00135" name="l00135"></a><span class="lineno">  135</span><span class="comment"> * @return A closure that will time and execute `function()`, adding the elapsed time to `accumulator`.</span></div>
<div class="line"><a id="l00136" name="l00136"></a><span class="lineno">  136</span><span class="comment"> */</span></div>
<div class="line"><a id="l00137" name="l00137"></a><span class="lineno">  137</span><span class="keyword">template</span>&lt;<span class="keyword">typename</span> Accumulator, <span class="keyword">typename</span> Func&gt;</div>
<div class="line"><a id="l00138" name="l00138"></a><span class="lineno">  138</span><span class="keyword">auto</span> <a class="code hl_function" href="namespaceflow_1_1perf.html#a0dee22ec7bf250bbbf556a7e15c1f784">timed_function</a>(<a class="code hl_enumeration" href="namespaceflow_1_1perf.html#ad61fb186191e4bb824d14601d11a2eb0">Clock_type</a> clock_type, Accumulator* accumulator, Func&amp;&amp; function);</div>
<div class="line"><a id="l00139" name="l00139"></a><span class="lineno">  139</span><span class="comment"></span> </div>
<div class="line"><a id="l00140" name="l00140"></a><span class="lineno">  140</span><span class="comment">/**</span></div>
<div class="line"><a id="l00141" name="l00141"></a><span class="lineno">  141</span><span class="comment"> * Constructs a closure that times and executes non-`void`-returning `function()`, adding the elapsed time with</span></div>
<div class="line"><a id="l00142" name="l00142"></a><span class="lineno">  142</span><span class="comment"> * clock type `clock_type` -- as raw ticks of perf::Duration -- to `accumulator`.  &quot;Nvr&quot; stands for</span></div>
<div class="line"><a id="l00143" name="l00143"></a><span class="lineno">  143</span><span class="comment"> * non-`void`-returning.</span></div>
<div class="line"><a id="l00144" name="l00144"></a><span class="lineno">  144</span><span class="comment"> *</span></div>
<div class="line"><a id="l00145" name="l00145"></a><span class="lineno">  145</span><span class="comment"> * Consider other overload(s) and similarly named functions as well.  With this one you get:</span></div>
<div class="line"><a id="l00146" name="l00146"></a><span class="lineno">  146</span><span class="comment"> *   - `function()` is treated as returning non-`void` (any return value returned by it is then returned</span></div>
<div class="line"><a id="l00147" name="l00147"></a><span class="lineno">  147</span><span class="comment"> *     by the returned closure accordingly).</span></div>
<div class="line"><a id="l00148" name="l00148"></a><span class="lineno">  148</span><span class="comment"> *     - Hence `function()` cannot be a `boost.asio` handler, which are always `void`-returning.</span></div>
<div class="line"><a id="l00149" name="l00149"></a><span class="lineno">  149</span><span class="comment"> *       So there is no timed_handler() counterpart to the present function.</span></div>
<div class="line"><a id="l00150" name="l00150"></a><span class="lineno">  150</span><span class="comment"> *   - Otherwise identical to the similar timed_function().</span></div>
<div class="line"><a id="l00151" name="l00151"></a><span class="lineno">  151</span><span class="comment"> *</span></div>
<div class="line"><a id="l00152" name="l00152"></a><span class="lineno">  152</span><span class="comment"> * ### Synopsis/examples ###</span></div>
<div class="line"><a id="l00153" name="l00153"></a><span class="lineno">  153</span><span class="comment"> * Similar to the 2nd example in timed_function() doc header: Time a function that happens to take a couple of args,</span></div>
<div class="line"><a id="l00154" name="l00154"></a><span class="lineno">  154</span><span class="comment"> * allowing for concurrency by using an `atomic`.  The difference: `timed_func()` returns a value.</span></div>
<div class="line"><a id="l00155" name="l00155"></a><span class="lineno">  155</span><span class="comment"> *</span></div>
<div class="line"><a id="l00156" name="l00156"></a><span class="lineno">  156</span><span class="comment"> *   ~~~</span></div>
<div class="line"><a id="l00157" name="l00157"></a><span class="lineno">  157</span><span class="comment"> *   std::atomic&lt;flow::perf::duration_rep_t&gt; accumulated_ticks(0);</span></div>
<div class="line"><a id="l00158" name="l00158"></a><span class="lineno">  158</span><span class="comment"> *   const auto timed_func</span></div>
<div class="line"><a id="l00159" name="l00159"></a><span class="lineno">  159</span><span class="comment"> *     = flow::perf::timed_function_nvr</span></div>
<div class="line"><a id="l00160" name="l00160"></a><span class="lineno">  160</span><span class="comment"> *         (flow::perf::Clock_type::S_CPU_THREAD_TOTAL_HI_RES, &amp;accumulated_ticks,</span></div>
<div class="line"><a id="l00161" name="l00161"></a><span class="lineno">  161</span><span class="comment"> *          [](int x, int y) -&gt; int { for (auto i = 0; i &lt; (x * y); ++i) {} return i; });</span></div>
<div class="line"><a id="l00162" name="l00162"></a><span class="lineno">  162</span><span class="comment"> *   // ...</span></div>
<div class="line"><a id="l00163" name="l00163"></a><span class="lineno">  163</span><span class="comment"> *   // Later, run it -- this will add to accumulated_ticks.  Can do this many times *and* concurrently in N threads.</span></div>
<div class="line"><a id="l00164" name="l00164"></a><span class="lineno">  164</span><span class="comment"> *   const auto result = timed_func(7, 7); // Note it is called non-void-style, with the return value passed-through.</span></div>
<div class="line"><a id="l00165" name="l00165"></a><span class="lineno">  165</span><span class="comment"> *   // ...</span></div>
<div class="line"><a id="l00166" name="l00166"></a><span class="lineno">  166</span><span class="comment"> *   // Later, here&#39;s the result.  Note the construction from type-unsafe ticks to type-safe Duration.</span></div>
<div class="line"><a id="l00167" name="l00167"></a><span class="lineno">  167</span><span class="comment"> *   const flow::perf::Duration total_dur(accumulated_ticks);</span></div>
<div class="line"><a id="l00168" name="l00168"></a><span class="lineno">  168</span><span class="comment"> *   // Can convert to whatever units type-safely now (duration_cast&lt;&gt; in this case allows for precision loss).</span></div>
<div class="line"><a id="l00169" name="l00169"></a><span class="lineno">  169</span><span class="comment"> *   const auto total_dur_us = chrono::duration_cast&lt;chrono::microseconds&gt;(total_dur);</span></div>
<div class="line"><a id="l00170" name="l00170"></a><span class="lineno">  170</span><span class="comment"> *   ~~~</span></div>
<div class="line"><a id="l00171" name="l00171"></a><span class="lineno">  171</span><span class="comment"> *</span></div>
<div class="line"><a id="l00172" name="l00172"></a><span class="lineno">  172</span><span class="comment"> * ### `Accumulator A` type requirements/recommendations ###</span></div>
<div class="line"><a id="l00173" name="l00173"></a><span class="lineno">  173</span><span class="comment"> * See timed_function().</span></div>
<div class="line"><a id="l00174" name="l00174"></a><span class="lineno">  174</span><span class="comment"> *</span></div>
<div class="line"><a id="l00175" name="l00175"></a><span class="lineno">  175</span><span class="comment"> * @tparam Accumulator</span></div>
<div class="line"><a id="l00176" name="l00176"></a><span class="lineno">  176</span><span class="comment"> *         See timed_function().</span></div>
<div class="line"><a id="l00177" name="l00177"></a><span class="lineno">  177</span><span class="comment"> * @tparam Func</span></div>
<div class="line"><a id="l00178" name="l00178"></a><span class="lineno">  178</span><span class="comment"> *         A function that is called non-`void`-style taking any arbitrary number of args, possibly none.</span></div>
<div class="line"><a id="l00179" name="l00179"></a><span class="lineno">  179</span><span class="comment"> * @param clock_type</span></div>
<div class="line"><a id="l00180" name="l00180"></a><span class="lineno">  180</span><span class="comment"> *        The type of clock to use for timing `function()`.</span></div>
<div class="line"><a id="l00181" name="l00181"></a><span class="lineno">  181</span><span class="comment"> * @param accumulator</span></div>
<div class="line"><a id="l00182" name="l00182"></a><span class="lineno">  182</span><span class="comment"> *        The accumulator to add time elapsed when calling `function()` to.  See instructions above regarding</span></div>
<div class="line"><a id="l00183" name="l00183"></a><span class="lineno">  183</span><span class="comment"> *        concurrency, `atomic`, etc.</span></div>
<div class="line"><a id="l00184" name="l00184"></a><span class="lineno">  184</span><span class="comment"> * @param function</span></div>
<div class="line"><a id="l00185" name="l00185"></a><span class="lineno">  185</span><span class="comment"> *        The function to execute and time.</span></div>
<div class="line"><a id="l00186" name="l00186"></a><span class="lineno">  186</span><span class="comment"> * @return A closure that will time and execute `function()`, adding the elapsed time to `accumulator`.</span></div>
<div class="line"><a id="l00187" name="l00187"></a><span class="lineno">  187</span><span class="comment"> */</span></div>
<div class="line"><a id="l00188" name="l00188"></a><span class="lineno">  188</span><span class="keyword">template</span>&lt;<span class="keyword">typename</span> Accumulator, <span class="keyword">typename</span> Func&gt;</div>
<div class="line"><a id="l00189" name="l00189"></a><span class="lineno">  189</span><span class="keyword">auto</span> <a class="code hl_function" href="namespaceflow_1_1perf.html#a58d2f7a7fca0c3cfd0a87ae560ce4926">timed_function_nvr</a>(<a class="code hl_enumeration" href="namespaceflow_1_1perf.html#ad61fb186191e4bb824d14601d11a2eb0">Clock_type</a> clock_type, Accumulator* accumulator, Func&amp;&amp; function);</div>
<div class="line"><a id="l00190" name="l00190"></a><span class="lineno">  190</span><span class="comment"></span> </div>
<div class="line"><a id="l00191" name="l00191"></a><span class="lineno">  191</span><span class="comment">/**</span></div>
<div class="line"><a id="l00192" name="l00192"></a><span class="lineno">  192</span><span class="comment"> * Identical to timed_function() but suitable for boost.asio-targeted handler functions.  In other words, if you want</span></div>
<div class="line"><a id="l00193" name="l00193"></a><span class="lineno">  193</span><span class="comment"> * to `post(handler)` or `async_...(handler)` in a boost.asio `Task_engine`, and you&#39;d like to time `handler()` when</span></div>
<div class="line"><a id="l00194" name="l00194"></a><span class="lineno">  194</span><span class="comment"> * it is executed by boost.asio, then use `timed_handler(..., handler)`.</span></div>
<div class="line"><a id="l00195" name="l00195"></a><span class="lineno">  195</span><span class="comment"> *</span></div>
<div class="line"><a id="l00196" name="l00196"></a><span class="lineno">  196</span><span class="comment"> * Consider other overload(s) and similarly named functions as well.  With this one you get:</span></div>
<div class="line"><a id="l00197" name="l00197"></a><span class="lineno">  197</span><span class="comment"> *   - `handler()` is a `boost.asio` or flow::async *handler*.</span></div>
<div class="line"><a id="l00198" name="l00198"></a><span class="lineno">  198</span><span class="comment"> *   - Otherwise identical to the similar timed_function().</span></div>
<div class="line"><a id="l00199" name="l00199"></a><span class="lineno">  199</span><span class="comment"> *</span></div>
<div class="line"><a id="l00200" name="l00200"></a><span class="lineno">  200</span><span class="comment"> * @note This is suitable for using the Flow-recommended boost.asio wrapper/helper API, flow::async.</span></div>
<div class="line"><a id="l00201" name="l00201"></a><span class="lineno">  201</span><span class="comment"> * @warning Using `timed_function(handler)` would &quot;work&quot; too, in that it would compile and at a first glance appear to</span></div>
<div class="line"><a id="l00202" name="l00202"></a><span class="lineno">  202</span><span class="comment"> *          work fine.  The problem: If `handler` is bound to an executor -- most commonly a boost.asio strand</span></div>
<div class="line"><a id="l00203" name="l00203"></a><span class="lineno">  203</span><span class="comment"> *          (util::Strand) -- then using timed_function() would &quot;unbind it.&quot;  So it it was bound to `Strand S`, meant</span></div>
<div class="line"><a id="l00204" name="l00204"></a><span class="lineno">  204</span><span class="comment"> *          to make certain `handler()` never executed concurrently with other handlers bound to `S`, then that</span></div>
<div class="line"><a id="l00205" name="l00205"></a><span class="lineno">  205</span><span class="comment"> *          constraint would (silently!) no longer be observed -- leading to terrible intermittent concurrency bugs.</span></div>
<div class="line"><a id="l00206" name="l00206"></a><span class="lineno">  206</span><span class="comment"> * @note boost.asio handlers always return `void` (meaning anything else they might return is ignored).  Hence there is</span></div>
<div class="line"><a id="l00207" name="l00207"></a><span class="lineno">  207</span><span class="comment"> *       no `timed_handler_nvr()`, even though there is a timed_function_nvr().</span></div>
<div class="line"><a id="l00208" name="l00208"></a><span class="lineno">  208</span><span class="comment"> *</span></div>
<div class="line"><a id="l00209" name="l00209"></a><span class="lineno">  209</span><span class="comment"> * ### Synopsis/examples ###</span></div>
<div class="line"><a id="l00210" name="l00210"></a><span class="lineno">  210</span><span class="comment"> * Similar to the 2nd example in timed_function() doc header: Time a function that happens to take a couple of args,</span></div>
<div class="line"><a id="l00211" name="l00211"></a><span class="lineno">  211</span><span class="comment"> * allowing for concurrency by using an `atomic`.  The difference: it is first bound to a strand.</span></div>
<div class="line"><a id="l00212" name="l00212"></a><span class="lineno">  212</span><span class="comment"> * In this case we `post()` the handler, so it takes no args in this example.  However, if used with, say,</span></div>
<div class="line"><a id="l00213" name="l00213"></a><span class="lineno">  213</span><span class="comment"> * `boost::asio::ip::tcp::socket::async_read_some()`, it would take args such as bytes-received and error code.</span></div>
<div class="line"><a id="l00214" name="l00214"></a><span class="lineno">  214</span><span class="comment"> *</span></div>
<div class="line"><a id="l00215" name="l00215"></a><span class="lineno">  215</span><span class="comment"> *   ~~~</span></div>
<div class="line"><a id="l00216" name="l00216"></a><span class="lineno">  216</span><span class="comment"> *   flow::util::Task_engine multi_threaded_engine; // boost.asio Task_engine later associated with 2+ threads.</span></div>
<div class="line"><a id="l00217" name="l00217"></a><span class="lineno">  217</span><span class="comment"> *   // ...</span></div>
<div class="line"><a id="l00218" name="l00218"></a><span class="lineno">  218</span><span class="comment"> *   // Strand guaranteeing non-concurrency for any handler functions bound to it, perhaps pertaining to HTTP request R.</span></div>
<div class="line"><a id="l00219" name="l00219"></a><span class="lineno">  219</span><span class="comment"> *   flow::util::Strand this_request_strand(multi_threaded_engine);</span></div>
<div class="line"><a id="l00220" name="l00220"></a><span class="lineno">  220</span><span class="comment"> *   std::atomic&lt;flow::perf::duration_rep_t&gt; accumulated_ticks(0);</span></div>
<div class="line"><a id="l00221" name="l00221"></a><span class="lineno">  221</span><span class="comment"> *   auto timed_hnd</span></div>
<div class="line"><a id="l00222" name="l00222"></a><span class="lineno">  222</span><span class="comment"> *     = flow::perf::timed_handler</span></div>
<div class="line"><a id="l00223" name="l00223"></a><span class="lineno">  223</span><span class="comment"> *         (flow::perf::Clock_type::S_CPU_THREAD_TOTAL_HI_RES, &amp;accumulated_ticks,</span></div>
<div class="line"><a id="l00224" name="l00224"></a><span class="lineno">  224</span><span class="comment"> *          boost::asio::bind_executor(this_request_strand,</span></div>
<div class="line"><a id="l00225" name="l00225"></a><span class="lineno">  225</span><span class="comment"> *                                     []() { for (unsigned int i = 0; i &lt; 1000000; ++i) {} });</span></div>
<div class="line"><a id="l00226" name="l00226"></a><span class="lineno">  226</span><span class="comment"> *   // Post it for ASAP execution -- *when* it asynchronously executed in some thread, will add to accumulated_ticks.</span></div>
<div class="line"><a id="l00227" name="l00227"></a><span class="lineno">  227</span><span class="comment"> *   // timed_hnd() is bound to this_request_strand, because the function we passed to timed_handler() was so bound.</span></div>
<div class="line"><a id="l00228" name="l00228"></a><span class="lineno">  228</span><span class="comment"> *   boost::asio::post(multi_threaded_engine, timed_hnd);</span></div>
<div class="line"><a id="l00229" name="l00229"></a><span class="lineno">  229</span><span class="comment"> *   // ...</span></div>
<div class="line"><a id="l00230" name="l00230"></a><span class="lineno">  230</span><span class="comment"> *   // Later, here&#39;s the result.  Note the construction from type-unsafe ticks to type-safe Duration.</span></div>
<div class="line"><a id="l00231" name="l00231"></a><span class="lineno">  231</span><span class="comment"> *   const flow::perf::Duration total_dur(accumulated_ticks);</span></div>
<div class="line"><a id="l00232" name="l00232"></a><span class="lineno">  232</span><span class="comment"> *   // Can convert to whatever units type-safely now (duration_cast&lt;&gt; in this case allows for precision loss).</span></div>
<div class="line"><a id="l00233" name="l00233"></a><span class="lineno">  233</span><span class="comment"> *   const auto total_dur_us = chrono::duration_cast&lt;chrono::microseconds&gt;(total_dur);</span></div>
<div class="line"><a id="l00234" name="l00234"></a><span class="lineno">  234</span><span class="comment"> *   ~~~</span></div>
<div class="line"><a id="l00235" name="l00235"></a><span class="lineno">  235</span><span class="comment"> *</span></div>
<div class="line"><a id="l00236" name="l00236"></a><span class="lineno">  236</span><span class="comment"> * ### `Accumulator A` type requirements/recommendations ###</span></div>
<div class="line"><a id="l00237" name="l00237"></a><span class="lineno">  237</span><span class="comment"> * See timed_function().</span></div>
<div class="line"><a id="l00238" name="l00238"></a><span class="lineno">  238</span><span class="comment"> *</span></div>
<div class="line"><a id="l00239" name="l00239"></a><span class="lineno">  239</span><span class="comment"> * @tparam Accumulator</span></div>
<div class="line"><a id="l00240" name="l00240"></a><span class="lineno">  240</span><span class="comment"> *         See timed_function().</span></div>
<div class="line"><a id="l00241" name="l00241"></a><span class="lineno">  241</span><span class="comment"> * @tparam Handler</span></div>
<div class="line"><a id="l00242" name="l00242"></a><span class="lineno">  242</span><span class="comment"> *         Handler meant to be `post()`ed or otherwise async-executed on a `Task_engine`. Can take any arbitrary number</span></div>
<div class="line"><a id="l00243" name="l00243"></a><span class="lineno">  243</span><span class="comment"> *         of args, possibly none.</span></div>
<div class="line"><a id="l00244" name="l00244"></a><span class="lineno">  244</span><span class="comment"> * @param clock_type</span></div>
<div class="line"><a id="l00245" name="l00245"></a><span class="lineno">  245</span><span class="comment"> *        See timed_function().</span></div>
<div class="line"><a id="l00246" name="l00246"></a><span class="lineno">  246</span><span class="comment"> * @param accumulator</span></div>
<div class="line"><a id="l00247" name="l00247"></a><span class="lineno">  247</span><span class="comment"> *        See timed_function().</span></div>
<div class="line"><a id="l00248" name="l00248"></a><span class="lineno">  248</span><span class="comment"> * @param handler</span></div>
<div class="line"><a id="l00249" name="l00249"></a><span class="lineno">  249</span><span class="comment"> *        The handler to execute and time.</span></div>
<div class="line"><a id="l00250" name="l00250"></a><span class="lineno">  250</span><span class="comment"> * @return A closure that will time and execute `handler()`, adding the elapsed time to `accumulator`; bound</span></div>
<div class="line"><a id="l00251" name="l00251"></a><span class="lineno">  251</span><span class="comment"> *         to the same executor (if any; e.g., a util::Strand) to which `handler` is bound.</span></div>
<div class="line"><a id="l00252" name="l00252"></a><span class="lineno">  252</span><span class="comment"> */</span></div>
<div class="line"><a id="l00253" name="l00253"></a><span class="lineno">  253</span><span class="keyword">template</span>&lt;<span class="keyword">typename</span> Accumulator, <span class="keyword">typename</span> Handler&gt;</div>
<div class="line"><a id="l00254" name="l00254"></a><span class="lineno">  254</span><span class="keyword">auto</span> <a class="code hl_function" href="namespaceflow_1_1perf.html#a7a3694bcd6e4bd506715d5931bc0c009">timed_handler</a>(<a class="code hl_enumeration" href="namespaceflow_1_1perf.html#ad61fb186191e4bb824d14601d11a2eb0">Clock_type</a> clock_type, Accumulator* accumulator, Handler&amp;&amp; handler);</div>
<div class="line"><a id="l00255" name="l00255"></a><span class="lineno">  255</span><span class="comment"></span> </div>
<div class="line"><a id="l00256" name="l00256"></a><span class="lineno">  256</span><span class="comment">/**</span></div>
<div class="line"><a id="l00257" name="l00257"></a><span class="lineno">  257</span><span class="comment"> * Prints string representation of the given `Checkpointing_timer` (whether with original data or an</span></div>
<div class="line"><a id="l00258" name="l00258"></a><span class="lineno">  258</span><span class="comment"> * aggregated-result timer) to the given `ostream`.  Note this is multi-line output that does *not* end in newline.</span></div>
<div class="line"><a id="l00259" name="l00259"></a><span class="lineno">  259</span><span class="comment"> *</span></div>
<div class="line"><a id="l00260" name="l00260"></a><span class="lineno">  260</span><span class="comment"> * @relatesalso Checkpointing_timer</span></div>
<div class="line"><a id="l00261" name="l00261"></a><span class="lineno">  261</span><span class="comment"> *</span></div>
<div class="line"><a id="l00262" name="l00262"></a><span class="lineno">  262</span><span class="comment"> * @param os</span></div>
<div class="line"><a id="l00263" name="l00263"></a><span class="lineno">  263</span><span class="comment"> *        Stream to which to write.</span></div>
<div class="line"><a id="l00264" name="l00264"></a><span class="lineno">  264</span><span class="comment"> * @param timer</span></div>
<div class="line"><a id="l00265" name="l00265"></a><span class="lineno">  265</span><span class="comment"> *        Object to serialize.</span></div>
<div class="line"><a id="l00266" name="l00266"></a><span class="lineno">  266</span><span class="comment"> * @return `os`.</span></div>
<div class="line"><a id="l00267" name="l00267"></a><span class="lineno">  267</span><span class="comment"> */</span></div>
<div class="line"><a id="l00268" name="l00268"></a><span class="lineno">  268</span>std::ostream&amp; <a class="code hl_function" href="namespaceflow_1_1perf.html#a5bb3a068357516df714c4266ec5c3df4">operator&lt;&lt;</a>(std::ostream&amp; os, <span class="keyword">const</span> <a class="code hl_class" href="classflow_1_1perf_1_1Checkpointing__timer.html">Checkpointing_timer</a>&amp; timer);</div>
<div class="line"><a id="l00269" name="l00269"></a><span class="lineno">  269</span> </div>
<div class="line"><a id="l00270" name="l00270"></a><span class="lineno">  270</span>} <span class="comment">// namespace flow::perf</span></div>
<div class="ttc" id="aclassflow_1_1perf_1_1Checkpointing__timer_html"><div class="ttname"><a href="classflow_1_1perf_1_1Checkpointing__timer.html">flow::perf::Checkpointing_timer</a></div><div class="ttdoc">The central class in the perf Flow module, this efficiently times the user's operation,...</div><div class="ttdef"><b>Definition:</b> <a href="checkpt__timer_8hpp_source.html#l00186">checkpt_timer.hpp:188</a></div></div>
<div class="ttc" id="aclock__type__fwd_8hpp_html"><div class="ttname"><a href="clock__type__fwd_8hpp.html">clock_type_fwd.hpp</a></div></div>
<div class="ttc" id="anamespaceflow_1_1perf_html"><div class="ttname"><a href="namespaceflow_1_1perf.html">flow::perf</a></div><div class="ttdoc">Flow module containing tools for profiling and optimization.</div><div class="ttdef"><b>Definition:</b> <a href="checkpt__timer_8cpp_source.html#l00024">checkpt_timer.cpp:25</a></div></div>
<div class="ttc" id="anamespaceflow_1_1perf_html_a09ba385403a0f347f283659a6e9d971b"><div class="ttname"><a href="namespaceflow_1_1perf.html#a09ba385403a0f347f283659a6e9d971b">flow::perf::Checkpointing_timer_ptr</a></div><div class="ttdeci">boost::shared_ptr&lt; Checkpointing_timer &gt; Checkpointing_timer_ptr</div><div class="ttdoc">Short-hand for ref-counting pointer to Checkpointing_timer.</div><div class="ttdef"><b>Definition:</b> <a href="perf__fwd_8hpp_source.html#l00043">perf_fwd.hpp:43</a></div></div>
<div class="ttc" id="anamespaceflow_1_1perf_html_a0dee22ec7bf250bbbf556a7e15c1f784"><div class="ttname"><a href="namespaceflow_1_1perf.html#a0dee22ec7bf250bbbf556a7e15c1f784">flow::perf::timed_function</a></div><div class="ttdeci">auto timed_function(Clock_type clock_type, Accumulator *accumulator, Func &amp;&amp;function)</div><div class="ttdoc">Constructs a closure that times and executes void-returning function(), adding the elapsed time with ...</div><div class="ttdef"><b>Definition:</b> <a href="timed__function_8hpp_source.html#l00032">timed_function.hpp:32</a></div></div>
<div class="ttc" id="anamespaceflow_1_1perf_html_a58d2f7a7fca0c3cfd0a87ae560ce4926"><div class="ttname"><a href="namespaceflow_1_1perf.html#a58d2f7a7fca0c3cfd0a87ae560ce4926">flow::perf::timed_function_nvr</a></div><div class="ttdeci">auto timed_function_nvr(Clock_type clock_type, Accumulator *accumulator, Func &amp;&amp;function)</div><div class="ttdoc">Constructs a closure that times and executes non-void-returning function(), adding the elapsed time w...</div><div class="ttdef"><b>Definition:</b> <a href="timed__function_8hpp_source.html#l00047">timed_function.hpp:47</a></div></div>
<div class="ttc" id="anamespaceflow_1_1perf_html_a5bb3a068357516df714c4266ec5c3df4"><div class="ttname"><a href="namespaceflow_1_1perf.html#a5bb3a068357516df714c4266ec5c3df4">flow::perf::operator&lt;&lt;</a></div><div class="ttdeci">std::ostream &amp; operator&lt;&lt;(std::ostream &amp;os, const Checkpointing_timer::Checkpoint &amp;checkpoint)</div><div class="ttdoc">Prints string representation of the given Checkpoint to the given ostream.</div><div class="ttdef"><b>Definition:</b> <a href="checkpt__timer_8cpp_source.html#l00335">checkpt_timer.cpp:335</a></div></div>
<div class="ttc" id="anamespaceflow_1_1perf_html_a7a3694bcd6e4bd506715d5931bc0c009"><div class="ttname"><a href="namespaceflow_1_1perf.html#a7a3694bcd6e4bd506715d5931bc0c009">flow::perf::timed_handler</a></div><div class="ttdeci">auto timed_handler(Clock_type clock_type, Accumulator *accumulator, Handler &amp;&amp;handler)</div><div class="ttdoc">Identical to timed_function() but suitable for boost.asio-targeted handler functions.</div><div class="ttdef"><b>Definition:</b> <a href="timed__handler_8hpp_source.html#l00033">timed_handler.hpp:33</a></div></div>
<div class="ttc" id="anamespaceflow_1_1perf_html_ad61fb186191e4bb824d14601d11a2eb0"><div class="ttname"><a href="namespaceflow_1_1perf.html#ad61fb186191e4bb824d14601d11a2eb0">flow::perf::Clock_type</a></div><div class="ttdeci">Clock_type</div><div class="ttdoc">Clock types supported by flow::perf module facilities, perf::Checkpointing_timer in particular.</div><div class="ttdef"><b>Definition:</b> <a href="clock__type__fwd_8hpp_source.html#l00066">clock_type_fwd.hpp:67</a></div></div>
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